Effect of high-doses pyrogallol on oxidative damage, transcriptional responses and microcystins synthesis in Microcystis aeruginosa TY001 (Cyanobacteria)

•Pyrogallol stress elevated the antioxidant enzymes activities of M. aeruginosa.•Pyrogallol stress caused lipid peroxidation to occur and malondialdehyde (MDA) levels to change.•High doses of pyrogallol significantly increased the MCs concentration in the medium.•Oxidative damage and DNA damage are the primary active mechanisms.

Severe eutrophication and harmful cyanobacterial blooms of freshwater ecosystems is a persistent environmental topic in recent decades. Pyrogallol (polyphenol) was confirmed to exhibit one of the most intensive inhibitory effects on the Microcystis aeruginosa. In this study, the expression of genes, release of microcystins (MCs) and antioxidant system of pyrogallol on Microcystis aeruginosa TY001 were investigated. The results revealed that the expression of stress response genes (prx, ftsH, grpE and fabZ) and DNA repair genes (recA and gyrB) were up-regulated. Meanwhile, the antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activity, were increased, and the stress caused lipid peroxidation to occur and malondialdehyde (MDA) levels to change. Unexpectedly, the relative transcript abundance of microcystin synthesis genes (mcyB, mcyD and ntcA) and the contents of microcystins (MCs) significantly increased compared with the control in the culture medium. In conclusion, oxidative damage and DNA damage are the primary mechanisms for the allelopathic effect of pyrogallol on M. aeruginosa TY001.